This invention is directed to new chemical compounds having a high proportion of nitrogen in their molecular structure. It is known that 5-(2-aminophenyl)-tetrazoles react with an aldehyde or ketone or with phosgene to produce 5,6-dihydrotetrazolo(1,5-C)quinazolines and tetrazolo(1,5-C)quinazolin-5(6H)one compounds respectively. The preparation and utility of these compounds as bronchodilators are described in U.S. Pat. Nos. 3,835,138 and 3,838,126. Other tetrazolo compounds of somewhat similar structure are described in U.S. Pat. No. 3,389,137.